Liquid system function indicator

ABSTRACT

In a constant volume liquid distribution system, a means to determine which liquid outlet means in a series of outlet means connected with a main pressure line is not receiving its proportional share of liquid. This is accomplished by monitoring the relationship of a primary and a secondary pressure within some acceptable limits to detect any malfunction in the system. Each outlet means includes a branch pressure line connected with the main line and passing through a proportioning block. Each block includes a pressure responsive valve means that monitors the aforementioned pressure relationship and operates as a result of varying pressures within the block due to malfunctions anywhere between the main line and the outlet from the respective outlet means. Valve operation causes a malfunction indicator for the same block to operate. Each block includes appropriate pressure and flow control fittings for apportioning liquid among the outlet means.

United States Patent (.91

Colgan et al. [4511 May 1, 1973 [s41 LIQUID SYSTEM FUNCTION I INDICATORPrimary Examin'erManuel A; Antonakas [75] Inventors: Francis E. Colgan,Midland Park; Au0mey sldney Faber at 11:18:] H. Reeve, River Vale, bothof [57] ABSTRACT [73] Assignee: Auto Research Corporation, Boon- In aconstant p liquid .distribution i a ton NJ. means to determine whichliquid outlet means in a series of outlet means connected with a mampressure [22] Filed: July 28, 1971 line is not receiving itsproportional share of liquid. {21] App]. NO: 166,721 This isaccomplished by monitoring the relationship of a primary and a secondarypressure within some acceptable limits to detect any malfunction in the3 D system. Each outlet means includes a branch pressure [51] Int. Cl...F16n 29/04 line c e ted with the main line and passing through Fleld0f a c l 8 R, 7 a proportioning block. Each block includes a pressure184/7 7 1 responsive valve means that monitors the aforemen- 242 tionedpressure relationship and operates as a result of varying pressureswithin the block due to malfunctions References Cited anywhere betweenthe main line and the outlet from the respective outlet means. Valveoperation causes a UNITED STATES PATENTS malfunction indicator for thesame block to operate. 3,098,500 7/1963 Gruber ..l37/556 x Ea h l ckincludes appropriate pressure and flow 2,691,773 10/1954Lichtenberger.... ..340/242 control fittings for apportioning liquidamong the out- 3,038,557 6/1962 Callahan ..l84/7 D let mean 3,526,2979/1970 Rotter et al..... 340/270 X 3,500,960 3/1970 Jaggi ..184/7 F 20Claims, 3 Drawing Figures x34 'g l 4/ j r A LIQUID SYSTEM FUNCTIONINDICATOR The present invention relates to a liquid distribution systemfunction indicating means for indicating whether the system is operatingproperly and for indicating the location of any malfunction in thesystem. This is accomplished by monitoring the relationship of a primaryand a secondary pressure in the system within some acceptable limits todetect any malfunction in'the system. The invention is preferably usedwith a constant volume system which dispenses a predictable volume ofliquid over time regardless of any blockages, leaks, pressurevariations, etc. Because volume remains constant, the variable pressurebecomes a useful malfunction indicator. I

In a specific application, the present invention is used in conjunctionwith a liquid lubricant pumping system. Hereafter only liquid lubricantwill be mentioned, but other appropriate liquids may be used.

One type of constant volume lubricant distribution system employs asingle pumping apparatus that feeds a main pressure line. Each of aseries of branch lines connected to the main line feeds a respectiveoutlet to deliver an apportioned share of the total lubricant flow to arespective bearing, or the like. In the event of a malfunction in abranch line or outlet, the remainder of the system will continue tooperate properly, while the malfunctioning section will deprive itsrespective bearing of needed lubricant, which may cause needless damage.If the pumping system is automatic and unattended or if the entiresystem is quite large, the malfunction in a singlebranch line or outletmay not be noticed for a long time. Appropriate means is required toalert an operator of the occurrence of a malfunction and to provide anindication as to theprecise location of the malfunction within thesystem.

In the prior art, sequential or cascading lubricant distributionarrangements are used to provide indications of proper system operationand to pinpoint where malfunctions have occurred. See, for example, U.S.Pat. No. 3,500,960, issued to Robert H. Jaggi, on Mar. 17, 1970,entitled Central Lubricating System of the SequentiallyOperating PistonValve Type," and aspiston enabled to shift. If the pressure indicator atthe end'of the series of pistons indicates completion of the cycle, itis assumed that all pistons have shifted and properly dispensedlubricant, when this might not be the case. With the present invention,on the other hand, such an assumption is not required as each individualdispensing block separately indicates the occurrence of a malfunction.

The above describedprior art system is-not sufficiently sensitive to aminor leak in a dispensing block. The reduced system pressure resultingfromthc leak would still be sufficient to shift the pistons and permitcompletion of a cycle, although at least one of the discharges oflubricant was insufficient. To cure this, the cycle completion sensingswitch can be made sufficiently sensitive to detect even a smallpressure deviation. However, oversensitivity may cause sensing ofnonexistent malfunctions or of minor leaks that would have insignificanteffect by the, time a cycle is Furtherrnore,,a cascadingsystemfrequently does not provide an indication for each branch line leadingto each outlet as to where the malfunction has occurred,

often because of the expense of such an installation.

rying pressure line. Each of a plurality of branch pressure lines leadsfrom the main pressure line to an individual proportioning outletthrough a respective proportioning block. Within the pro-portioningblock and in the branch line is located a primary lubricant flow controlfitting, which serves as a first control on the rate of flow oflubricant through the outlet. Further downstream on the branch line, andpreferably just upstream of its proportioning outlet, is positioned asecondary flow control fitting, which provides additional flow ratecontrol. The primary and secondary flow control fittings cooperate toapportion the lubricant flow through their respectiveoutlet. Because thepresent system is a constant volume one, the invention concerns sensingthe pressure between the primary and secondary fittings in each block tolocate a malfunction.

A primary malfunction indicating assembly communicates between theprimary and secondary flow control fittings in a block. That primaryassembly includes a sensing means connected with the main pressure linesuch that upon a reduction in the pressure between the aforesaid primaryand secondary fittings, as compared with the pressure in the mainpressure line, an indicator device will be actuated. That indicatordevice comprises a primary valve, including a shiftable valve spool,e.g., a piston, which on one side is operated upon by the pressure inthe main pressure line and on the other side is operated upon by thepressure between the primary andsecondary fittings. A spring cooperateswith the pressure between the fittings to retain the valve in theposition that indicates proper function. A reduction in the pressurebetween the fittings occurs when there is a malfunction or blockageupstream of or in the primary fitting and upstream of the connection ofthe primary assembly between the fittings or when there is a leakanywhere along the branch line.

Also communicating between the fittings isa secondary malfunctionindicating assembly, which operates in the event of certain malfunctionsto open the primary valve and permit the above noted malfunctionindicating leakage. The secondary assembly comprises a second indicatingvalve with a shiftable valve spool, e.g., a piston. i r

If there is a malfunction or a blockage in the secondary fitting or inthe branch line between the proportioning outlet from the branch lineand the primary fitting, there is a decrease in the flow of lubricantthrough the outlet from the, branch line and a consequent increase inthe pressure between the fittings. Eventually, this pressure build-upcauses the secondary valve to open, which immediately reduces thepressure behind the primary valve. The primary valve opens due to thereduction in pressure behind it.

A volume absorber, which may comprise a spring biased spool, e. g., apiston, also communicates between the fittings. The volume of the spacebetween the fittings that is available to hold lubricant, and thereforethe volume of lubricant between the fittings remains substantiallyconstant over an extended period of time. The only outlet from thisspace is the slow leakage past the secondary fitting. When the primaryvalve shifts due to a malfunction, this would reduce the space betweenthe fittings. However, since the volume of that space must remainconstant, the primary valve would not be able to shift unless the volumeabsorber also shifts to permit the primary valve to shift.

It is the primary object of the present invention to provide aneffective lubricant distribution system for a number of proportioningoutlets supplied by a single lubricant pressure source.

It is another object of the present invention to provide such a systemwith means for indicating a malfunction in the main pressure line and ineach branch line leading to each proportioning outlet.

It is still another object of the present invention to provide such asystem which is quite sensitive.

It is yet another object of the present invention to provide such asystem, which can proportion lubricant continuously.

These and other objects of the present invention will become apparentfrom the following description of the accompanying drawings, in which:

FIG. 1 schematically illustrates a lubricant distribu tion systememploying the present invention;

FIG. 2 is a cross-sectional view through a dispensing block for use inconjunction with the present invention; and

FIG. 3 is a schematic diagram of the dispensing block of FIG. 2.

FIG. 1 shows a centralized lubricant distribution system of the typetaught in U.S. Pat. No. 3,499,506, issued Mar. 10, 1970, to William E.Durnan and Paul H. Reeve, entitled Lubricant Distribution System, et al.and assigned to the assignee hereof. The system includes a supplyoflubricant, such as oil, and a pump 12. Pump 12 may supply lubricantunder pressure continuously or periodically as a particular applicationrequires.

The lubricant is pumped through main pressure line 14, which passesthrough all of proportioning blocks 20, described below. At the end ofline 14 is connecting conduit 16 which communicates with pressuresensing switch 18. Switch 18 might be a flow sensor which measures therate of lubricant flow. In the event of any unusual change in thepressure in main line 14, which would occur, for example, when pump 12is shut off, or line 14 is crimped or blocked, or there is a major leakin the system, then switch 18 actuates a signal that there is amalfunction in one ofthe above noted elements of the system.

Situated on line 14 are a plurality of substantially identicalproportioningblocks 20, each of which transmits an apportioned share oflubricant through its respective branch pressure line 22 and itsrespective proportioning outlet 24 to respective bearing 26 requiringlubrication.

Pressure line 14 may also directly deliver lubricant, without usingproportioning blocks, like 20, to noncritical bearings 28 where there islittle danger of damageresulting from 'a' malfunctioninthe system or inthe distribution of lubricant to these bearings. The connections fordelivering lubricant to such bearings are illustrated in dashed lineform in FIG. 1.

In FIGS. 2, and 3, a typical proportioning block 20 is illustrated. Mainpressure line 14 is connected with and passes through block 20 from mainpressure line inlet 32 through main pressure line outlet 34. The normalflow path through block 20 of an apportioned share of lubricant is frominlet 32 into the branch pressure line, meaning that it passes throughprimary flow'control fitting 36, pressure sensing conduit 38, secondarysensing conduit 39, branch pressure line portion 22, and secondary flowcontrol fitting 40 through outlet 24 at the end of line 22. For bestmalfunction indication, as described below, secondary fitting 40 isusually located remote from block 20 itself, rather than in the block,as as near as possible to outlet 24.

Both of the primary and secondary flow control fittings are standard andinclude an appropriately dimensioned opening to control flow. Inacontinuously operating system, both of the fittings merely control therate of flow. In a cyclic system, the secondary fitting 40 is of thetype which includes its own internal valve that inhibits lubricantbackflow and air leakage when lubricant is not being pumped, such asthat taught in U.S. Pat. 2,810,541, issued Oct. 22, 1957 to Thomas R.Thomas, entitled Flow Metering Unit, and assigned to the a'ssigneehereof.

As lubricant passes primary fitting 36, there is a first pressure drop.As it passes secondary fitting 40 and exits from the system, there is asecond pressure drop to zero. The flow resistances of fittings 36, 40may be in any proportion. In the preferred embodiment of the invention,the flow resistances of fittings 36 and 40 are equal so that thepressure in conduit 38 is half that in main line 14.

Main line 14 communicates through narrowed conduit 41 with valve 42.Conduit 38 also communicates with valve 42. When the pressure in conduit38 drops below a threshold level, valve 42 opens a leakage flow oflubricant from conduit 41, which passes through passage 43 and outlet44' where it serves as an indication as to where a system malfunctionhas occurred.

Valve 42 includes a pressure change reacting means, a spool, piston 46that moves through bore 45. Piston 46 includes a stiffly resilient valveelement 47, of rubber or the like, which is at the lower end of piston46. Its lower surface 48 is biased against flattened valve seat 49. Seat49 comprises the free upper edge of a rigid metal annular sleeve 50which has an opening through it that is included as part of conduit 41.Surface 48 of valve piston 46 must readily seal against seat 49 at theoperating pressures of the system. The seal must be secure not only atthe elevated pressures where a malfunction is being sensed, butfrequently at the greatly reduced pressures of an operating lubricatingsystem. These differing pressure levels are discussed further below.

Main pressure line 14 communicates through connecting conduit 41 withthe lower surface 48 of piston 46. Compression spring 52 seats at oneend against fixed spring seat 54 and at the other end presses againstsurface 56 of piston 46 to normally drive the piston against seat 49.

exposed to the reduced level of pressure in conduit 38.

The pressure on surface 56 combines with the force ex erted by spring 52to hold piston 46 against seat 49. When piston 46 shifts upward in FIG.2 off seat 49 upon the occurrence of a malfunction, as described below,an enlarged chamber is formed beneath surface 48 within bore 45.Immediately, the elevated pressure within conduit 41 is applied upon agreater area of surface 48 and helps drive piston 46 rapidly upwardagainst the force of spring 52 and the pressure in conduit 38.

' The periphery of piston 46 serves as a blocking means to close conduit43. When piston 46 eventually shifts upward sufficiently, lower edge 66of the piston opens malfunction indicating outlet conduit 43. Lubricantfrom line 14 leaks through conduits 41, 43 and outlet 44. This leakageindicates the location of the malfunction.

In the event of other types of malfunctions in block 20, instead ofdropping below a first threshold level, the pressure in conduit 38increases beyond a second threshold level. This holds valve 42 closed.But, conduit 38 also communicates with secondary valve 72, whichincludes its own reacting means that opens upon sufficient elevation ofthe pressure in conduit 38.-

Opening of valve 72 causes an immediate drop in the pressure in conduit38 below the first threshold level. This causes piston 46 to shiftwhich, through the chain of events described above, causes leakagethrough outlet 44 and locates the malfunction.

Secondary valve 72 includes a reacting means, a spool, piston 74, thelower surface 76 of which communicates directly with pressure conduit38. Normally a spool valve, like valve 72, would have some degree ofsponge or preshifting in its stationary original position. Thisundesired momentaryshifting of piston 74 might undesirably reduce thepressure in conduit 38. Since the operation of primary valve 42 istriggered by shifting of piston 74, piston 74 should be heldrigidly,sta-- tionary until an abnormal condition develops that shouldcause it to shift. Restraining means 78 holds piston 74 rigidlystationary in its primary position. Restraining means 78 comprises ashearable burst disc or a shearable metallic wire, or the like, havingknown burst strength. The wires of a typical restraining means 78 passthrough closely dimensioned openings in piston 74 and closelydimensioned openings in the cylinder walls surrounding piston 74. Therestraining means wire has sufficient rigidity to hold piston 74stationary. When the pressure in conduit 38 exceeds the second thresholdlevel, the force on piston 74 is sufficient to tear restraining means 78and permit piston 74 to jump outward, i.e., upward in FIG. 2. Thefreeend 82 of piston 74 may be so shaped and positioned with respect tothe casing of block 20 as to extend out of the block when piston 74shifts upward. This will provide an indication that the malfunction isone resulting from overpressure in conduit 38. As noted above, whenpiston 74 shifts, the sudden pressure reduction in conduit 38 results inopening of valve 42.

Before piston 46 shifts, conduit 38, branch line 22 upstrearh of fitting40 and the rest of the space between fittings 36, 40 is filled withliquid. While the liquid is at a lower pressure than that in main line14, it is still incompressible, whereby piston 46 would be preventedfrom ascending, in FIG. 2, because there would be no space for it tomove into. The slow bleed of pressure and liquid through fitting 40 isinsuffieient to absorb the necessarily rapid movement of piston 46.Conduit 38 also communicates with a volume absorber 90, which includes aspool, piston 92 having a surface 94 exposed to the pressure in conduit38. A shift in the lubricant in conduit 38 due to movement of piston 46causes piston 92 to shift to the left in FIG. 2. Spring 95 pressespiston 92 inward, i.e., to the right in FIG. 2. The spring permitspiston 92 to be continuously shifting gradually under varying volumesdeveloped within conduit 38. When lubricant is displaced by movement ofpiston 46, piston 92 shifts to keep constant the volume of the spaceavailable for the trapped liquid. Piston 92 shifts quite rapidly whenpiston 46 is moving. Preferably, the area of surface 94 is equal to thatof surface 56, so that piston 92 shifts to the same extent as piston 46.

Block 20 operates as follows. In the event that there are no blockages,leaks or malfunctions in the system, lubricant will properly flowthrough the desired pathway and outlet 24 without either of valves 42 or72 being affected. In the event of blockage, crimping, a leak or othermalfunction in main pressure line 14, the change in pressure in thatlinewould be sensed at pressure switch 18.

In the event of a blockage in or a malfunction of primary flow controlfitting 36 or upon the occurrence of other events noted above, thepressure in conduit 38 and on surface 56 of piston 46 declines. Spring52 alone is then insufficient to hold valve piston 46 closed, the valveopens, and the leakage through outlet 44 indicates the precise locationof the malfunction.

In the eventof a blockage in or a malfunction of secondary flow controlfitting 40 or upon the occurrence of other events noted above, the flowthrough fitting 40 declines. Since there is a reduction in the pressuredrop across fitting 40, the pressure in conduit 38 correspondinglyrises. The elevated pressure on surface 56 of valve piston 46 preventsshifting of the piston. Increasing pressure will eventually cause valve72 to open, which, as described above, thereafter causes valve 42 toopen and causes the malfunction indicating flow of lubricant throughoutlet 44. Thus, no matter what type of malfunction occurs in thesystem, it will be indicated.

As noted above, secondary flow control fitting 40 is located as close tooutlet 24 as possible. As described herein, any malfunctions in thatfitting or upstream thereof will, therefore, be reflected in themalfunction indication provided by block 20. If secondary fitting 40were included in or close to dispensing block 20, then all of the lengthof outlet conduit 22 downstream of that fitting might not receive thebenefit of the malfunction indication which the present invention isdesigned to provide.

Were the system pressure in main pressure line 14 sufficiently high, thesystem would be continuously testing itself for malfunction andcontinuously indicatsystems run at very low pressures. At such pressuresand volumes, it is impractical to continuously test because insufficientpressures are developed to cause the necessary piston shiftings due topressure differentials. Periodic testing at elevated pressures would berequired. A system might normally operate at 25-50 psi. Some systemscould be expected to operate at as low as l0 psi. A suitable testpressure would be on the order of 300 psi.

There has just been described a novel lubricant distribution systemadaptable for use for continuous lubricant distribution, where anindication of a malfunction in the system can readily be obtained andthe precise location of the malfunction can readily be ascertained.

Although this invention has been described with respect to its preferredembodiments, it should be understood that many variations andmodifications will now be obvious to those skilled in the art, and it ispreferred, therefore, that the scope of the invention be limited not bythe specific disclosure herein, but only by the appended claims.

We claim:

1. A liquid distribution system comprising:

a main liquid carrying pressure line; a supply of liquid under pressurecommunicating with said main pressure line;

at least one liquid carrying branch pressure line for carrying liquid toa proportioning outlet, and a proportioning outlet at the end of said atleast one branch line;

connected into said branch line are a primary liquid flow controlfitting and, downstream of said primary fitting, a secondary liquid flowcontrol fitting, which fittings cooperate to apportion the flow rateofliquid to said proportioning outlet;

valve means communicating with said branch line between said primary andsaid secondary fittings to be operated upon by the branch line pressurebetween said fittings; said valve means including first reacting meansfor reacting to a variation in the branch line pressure between saidfittings;

indicator means connected with said reacting means for indicating whensaid reacting means have reacted to a change in the aforesaid pressure.

2. A liquid distribution system comprising:

a main liquid carrying pressure line; a supply of liquid under pressurecommunicating with said main pressure line;

at least one liquid carrying branch pressure line for carrying liquid toa proportioning outlet, and a proportioning outlet at the end of said atleast one branch line;

connected into said branch line are a primary liquid flow controlfitting and, downstream ofsaid primary fitting, a secondary liquid flowcontrol fitting, which fittings cooperate to apportion the flow rate ofliquid to said proportioning outlet;

valve means communicating on the one hand with said main line to beoperated upon by the main line pressure and communicating on the otherhand with said branch line between said primary and said secondaryfittings to be operated upon by the branch line pressure between saidfittings; said valve means including first reacting means for reactingto a variation in the branch line pressure between said fittings, incomparison to the main line pressure;

indicator means connected with said reacting means for indicating whensaid reacting means have reacted to a change in the aforesaidcomparative pressures. 3. The liquid distribution system of claim 2,wherein said secondary fitting is positioned near said proportioningoutlet.

4. The liquid distribution system of claim 2, wherein said indicatormeans comprises a separate outlet from said main line;

said reacting means comprises blocking means adapted to normally blocksaid separate outlet; said blocking means being adapted to open saidseparate outlet based upon the comparative pressures in said main andsaid branch line when the difference in pressures exceeds a firstthreshold level and it is the branch line pressure that has decreased tobring about the variation. 5. The liquid distribution system of claim 2,wherein said valve means comprises first valve means and second valvemeans;

said first valve means communicating on the one hand with said main lineto be operated upon by the main line pressure and communicating on theother hand with said branch line between said pri mary and secondaryfitting to be operated upon by the branch line pressure between saidfittings; said reacting means being a part of said first valve means andreacting to a variation in the comparative pressures of said main andsaid branch lines when the difference in pressures exceeds the firstthreshold level and it is the branch line pressure that has decreased tobring about the variation;

said second valve meanscommunicating with said branch line between saidfittings; said second valve means including second reacting means forreacting when the branch line pressure between said fittings exceeds asecond threshold level;

said indicator means also being connected with said second reactingmeans for indicating when said second reacting means has reacted tobranch line pressure above the second threshold level.

6. The liquid distribution system of claim 5, wherein said indicatingmeans comprises a separate outlet from said main line;

said reacting means comprises blocking means adapted to normally blocksaid separate outlet; said blocking means being adapted to open saidseparate outlet based upon the comparative pressures in said main andsaid branch line when the difference in pressures exceeds a firstthreshold level and it is the branch line pressure that has decreased tobring about the variation.

7. The liquid distribution system of claim 5, wherein said second valvemeans comprises a second shiftable spool, which is shiftable to increasethe space for liquid in said branch line between said fittings;

movement restraining means being connected to said second spool andadapted to prevent shifting of that spool until said second thresholdlevel of pressure in said branch line between said fittings is exceeded.

8. The liquid distribution system of claim 5, wherein said primaryfitting, said first valve means, a portion of said main pressure line,including a connection between said main pressure line and said branchline, and said indicator means are all incorporated within a unitaryproportioning block.

, 9. The liquid distribution system of claim 2, wherein said valve meansincludes first valve means, which comprises a first shiftable spool; onone operative surface, said first spool is exposed to the main linepressure, which would cause said first spool to move in a firstdirection; on a second operative surface, said first spool is exposed tothe branch line pressure between said primary and said secondaryfittings, which branch line pressure would cause said first spool tomove in the direction opposite said first direction;

said reacting means being part of said first valve means and beingpositioned to be acted upon and thereby to react to the movement of saidfirst spool.

10. The liquid distribution system of claim 9, further comprising abiasing means connected with so as to operate upon said first spool tobias said first spool in the said opposite direction.

1 1. The liquid distribution system of claim 9, wherein said reactingmeans comprises a separate outlet from said main line; and

said first spool includes blocking means for blocking said separateoutlet from said main line when said first spool is moved in saidopposite direction; and

' for opening said separate outlet when said first spool is moved insaid first direction, thereby permitting liquid to leak through saidseparate outlet.

12. The liquid distribution system of claim 11, wherein said valve meansfurther comprises a second valve means;

said second valve means communicating with said branch line between saidfittings; said second valve means including second reacting means forreacting when the branch line pressure between said fittings exceeds asecond threshold level;

said indicator means also being connected with said second reactingmeans for indicating when said second reacting means has reacted tobranch line pressure above the second threshold level.

13. The liquid distribution system of claim 12, wherein said secondvalve means comprises a second shiftable spool, which is shiftable toincrease the space for liquid in said branch line between said fittings;

movement restraining means being connected to said second spool andadapted to prevent shifting of that spool until said second thresholdlevel of pres sure in said branch line between said fittings isexceeded.

14. The liquid distribution system of claim 13, wherein said restrainingmeans comprises a shearable means with a burst strength selected topermit shifting of said second spool at the pressure exceeding saidsecond threshold level.

15. The liquid distribution system of claim 13, further comprising avolume adjustment means c0nnected with said branch line between saidfittings for increasing the available space for liquid between saidfittings when said first spool shifts in said first direction.

16. The liquid distribution system of claim 15,

wherein said volume adjustment means comprises a third shiftable spool,which 18 spring biased to ecrease the space between said fittings.

17. The liquid distribution system of claim 16, wherein said secondaryfitting is positioned near said proportioning outlet from said branchline.

18. The liquid distribution system of claim 17, wherein said primaryfitting, said first valve means, a portion of said main pressure line,including a connection between said main pressure line and said branchline, and said indicator means all incorporated within a unitaryproportioning block.

19. The liquid distribution system of claim 18, comprising a pressuresensor and indicator communicating with said main pressure line forindicating particular variations in pressure in said main pressure line.

20. The liquid distribution system of claim 9, further comprising avolume adjustment means connected with said branch line between saidfittings for increasing the available space for liquid between saidfittings when said first spool shifts in said first direction.

1. A liquid distribution system comprising: a main liquid carryingpressure line; a supply of liquid under pressure communicating with saidmain pressure line; at least one liquid carrying branch pressure linefor carrying liquid to a proportioning outlet, and a proportioningoutlet at the end of said at least one branch line; connected into saidbranch line are a primary liquid flow control fitting and, downstream ofsaid primary fitting, a secondary liquid flow control fitting, whichfittings cooperate to apportion the flow rate of liquid to saidproportioning outlet; valve means communicating with said branch linebetween said primary and said secondary fittings to be operated upon bythe branch line pressure between said fittings; said valve meansincluding first reacting means for reacting to a variation in the branchline pressure between said fittings; indicator means connected with saidreacting means for indicating when said reacting means have reacted to achange in the aforesaid pressure.
 2. A liquid distribution systemcomprising: a main liquid carrying pressure line; a supply of liquidunder pressure communicating with said main pressure line; at least oneliquid carrying branch pressure line for carrying liquid to aproportioning outlet, and a proportioning outlet at the end of said atleast one branch line; connected into said branch line are a primaryliquid flow control fitting and, downstream of said primary fitting, asecondary liquid flow control fitting, which fittings cooperate toapportion the flow rate of liquid to said proportioning outlet; valvemeans communicating on the one hand with said main line to be operatedupon by the main line pressure and communicating on the other hand withsaid branch line between said primary and said secondary fittings to beoperated upon by the branch line pressure between said fittings; saidvalve means including first reacting means for reacting to a variationin the branch line pressure between said fittings, in comparison to themain line pressure; indicator means connected with said reacting meansfor indicating when said reacting means have reacted to a change in theaforesaid comparative pressures.
 3. The liquid distribution system ofclaim 2, wherein said secondary fitting is positioned near saidproportioning outlet.
 4. The liquid distribution system of claim 2,wherein said indicator means comprises a separate outlet from said mainline; said reacting means comprises blocking means adapted to normallyblock said separate outlet; said blocking means being adapted to opensaid separate outlet based upon the comparative pressures in said mainand said branch line when the difference in pressures exceeds a firstthreshold level and it is the branch line pressure that has decreased tobring about the variation.
 5. The liquid distribution system of claim 2,wherein said valve means comprises first valve means and second valvemeans; said first valve means communicating on the one hand with saidmain line to be operated upon by the main line pressure andcommunicating on the other hand with said branch line between saidprimary and secondary fitting to be operated upon by the branch linepressure between said fittings; said reacting means being a part of saidfirst valve means and reacting to a variation in the comparativepressures of said main and said branch lines when the difference inpressures exceeds the first threshold level and it is the branch linepressure that has decreased to bring about the variation; said secondvalve means communicating with said branch line between said fittings;said second valve means including second reacting means for reactingwhen the branch line pressure between said fittings exceeds a secondthreshold level; said indicator means also being connected with saidsecond reacting means for indicating when said second reacting means hasreacted to branch line pressure above the second threshold level.
 6. Theliquid distribution system of claim 5, wherein said indicating meanscomprises a separate outlet from said main line; said reacting meanscomprises blocking means adapted to normally block said separate outlet;said blocking means being adapted to open said separate outlet basedupon the comparative pressures in said main and said branch line whenthe difference in pressures exceeds a first threshold level and it isthe branch line pressure that has decreased to bring about thevariation.
 7. The liquid distribution system of claim 5, wherein saidsecond valve means comprises a second shiftable spool, which isshiftable to increase the space for liquid in said branCh line betweensaid fittings; movement restraining means being connected to said secondspool and adapted to prevent shifting of that spool until said secondthreshold level of pressure in said branch line between said fittings isexceeded.
 8. The liquid distribution system of claim 5, wherein saidprimary fitting, said first valve means, a portion of said main pressureline, including a connection between said main pressure line and saidbranch line, and said indicator means are all incorporated within aunitary proportioning block.
 9. The liquid distribution system of claim2, wherein said valve means includes first valve means, which comprisesa first shiftable spool; on one operative surface, said first spool isexposed to the main line pressure, which would cause said first spool tomove in a first direction; on a second operative surface, said firstspool is exposed to the branch line pressure between said primary andsaid secondary fittings, which branch line pressure would cause saidfirst spool to move in the direction opposite said first direction; saidreacting means being part of said first valve means and being positionedto be acted upon and thereby to react to the movement of said firstspool.
 10. The liquid distribution system of claim 9, further comprisinga biasing means connected with so as to operate upon said first spool tobias said first spool in the said opposite direction.
 11. The liquiddistribution system of claim 9, wherein said reacting means comprises aseparate outlet from said main line; and said first spool includesblocking means for blocking said separate outlet from said main linewhen said first spool is moved in said opposite direction; and foropening said separate outlet when said first spool is moved in saidfirst direction, thereby permitting liquid to leak through said separateoutlet.
 12. The liquid distribution system of claim 11, wherein saidvalve means further comprises a second valve means; said second valvemeans communicating with said branch line between said fittings; saidsecond valve means including second reacting means for reacting when thebranch line pressure between said fittings exceeds a second thresholdlevel; said indicator means also being connected with said secondreacting means for indicating when said second reacting means hasreacted to branch line pressure above the second threshold level. 13.The liquid distribution system of claim 12, wherein said second valvemeans comprises a second shiftable spool, which is shiftable to increasethe space for liquid in said branch line between said fittings; movementrestraining means being connected to said second spool and adapted toprevent shifting of that spool until said second threshold level ofpressure in said branch line between said fittings is exceeded.
 14. Theliquid distribution system of claim 13, wherein said restraining meanscomprises a shearable means with a burst strength selected to permitshifting of said second spool at the pressure exceeding said secondthreshold level.
 15. The liquid distribution system of claim 13, furthercomprising a volume adjustment means connected with said branch linebetween said fittings for increasing the available space for liquidbetween said fittings when said first spool shifts in said firstdirection.
 16. The liquid distribution system of claim 15, wherein saidvolume adjustment means comprises a third shiftable spool, which isspring biased to decrease the space between said fittings.
 17. Theliquid distribution system of claim 16, wherein said secondary fittingis positioned near said proportioning outlet from said branch line. 18.The liquid distribution system of claim 17, wherein said primaryfitting, said first valve means, a portion of said main pressure line,including a connection between said main pressure line and said branchline, and said indicator means all incorporated within a unitaryproportioning block.
 19. The liquid distribution sysTem of claim 18,comprising a pressure sensor and indicator communicating with said mainpressure line for indicating particular variations in pressure in saidmain pressure line.
 20. The liquid distribution system of claim 9,further comprising a volume adjustment means connected with said branchline between said fittings for increasing the available space for liquidbetween said fittings when said first spool shifts in said firstdirection.